Microgravity-Induced Back Pain and Intervertebral Disc Herniation: International Space Station Results
- Paper number
IAC-15,A1,2,6,x31087
- Author
Dr. Jojo Sayson, University of California, San Diego, United States
- Coauthor
Dr. Alan Hargens, University of California, United States
- Coauthor
Dr. Jeffrey Lotz, Univerisity of California, United States
- Coauthor
Prof.Dr. Douglas Chang, Univerisity of California, United States
- Coauthor
Dr. Scott Parazynski, Arizona State University, United States
- Year
2015
- Abstract
There are yet unresolved spinal changes during and after microgravity exposure. Crewmembers frequently report moderate to severe back pain in space and upon return to Earth a high incidence of intervertebral disc (IVD) herniation in the cervical and lumbar spine. In response to NASA’s Critical Path Roadmap Risks and Questions regarding disc injury and higher incidence of HNPs after space flight (IRP Gap-B4), we are performing state-of-the art imaging analyses of crewmembers to investigate the mechanisms of in-flight back pain and IVD herniation post-flight. Twelve International Space Station (ISS) crewmembers are approved for participation in this study. To date, seven crew members have consented to our protocol and three have completed all pre-flight and post-flight testing. Crewmembers complete a battery of six tests before and after a 6 month mission to determine how the discs and other spinal structures change and whether anatomical alterations correlate with reported back pain. Pre-flight and post-flight baseline data are derived from six tests: 1. supine MRI lumbar and cervical spines (morphology/water content), 2. MR Spectroscopy (IVD metabolites), 3. Upright MRI (axial load with 10% bodyweight), 4. Spinal Kinematics with the KineGraph Vertebral Motion Analyzer (lumbar spine stiffness and stability), 5. Biering-Sorensen test (isometric endurance strength test of the back muscles), and 6. back pain and disability questionnaires. Comparative analyses of post-flight to pre-flight data indicate: 1) increased lumbar and cervical IVD heights observed in supine MRI scans, 2) increased axial compressibility of lumbar IVDs during upright MRI scans, 3) increased lumbar bending stiffness using Spinal Kinematics tests, 4) paraspinal muscle atrophy from MRI, and 4) increased low back pain post-flight using a Visual-Analog Scale. Countermeasures development for lumbar back pain on future spaceflights may include in-flight use of an axial compression device or spine compression maneuvers to prevent excessive IVD expansion and spinal column elongation, and exercises to provide Earth-like biomechanical stress with low-load, repetitive spine rotations. Crewmembers reported that a knee-to-chest position relieves in-flight lumbar pain. This manual compressive loading of the IVDs may counteract microgravity-induced supraphysiologic swelling of IVDs by fluid transfer across IVD endplates and into the vertebral body circulation. This project will define spine maladaptation during prolonged spaceflight and hopefully develop countermeasures to maintain crew’s performance and well-being. Supported by NASA grants NNX10AM18G and NNX13AM89G
- Abstract document
- Manuscript document
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